This section provides background information related to the present disclosure which is not necessarily prior art.
As the demand for electrical power increases during the day, the utility provider experiences an increase in the cost of generating electrical power as a result of secondary “peak” power plants that are switched on to supplement off-peak power generating plants. Many utility providers are consequently establishing real time energy price rates for charging the consumer a variable rate that increases as the cost of generating power increases during peak demand periods. These rates may vary based on a utility price rate schedule, which establishes a different usage price rate for a plurality of specified time periods of the day. Such energy price rates may also be periodically changed by a utility provider.
In situations where the peak demand begins to exceed the power generating capacity of the utility's off-peak and peak power plants, the utility may engage in demand side management by changing the price rate for electrical power during peak demand periods, in an effort to encourage consumers to reduce energy usage to keep energy demand from exceeding capacity. Utilities engaging in demand side management transmit a signal including information about an energy price rate in an attempt to encourage individuals to reduce the amount of energy used during peak demand periods.
In the example of an air conditioner controlled by a conventional thermostat, the user would be billed at a higher rate when the air conditioner runs during peak energy demand periods. Previous attempts have been made to provide a thermostat that receives a signal from a utility provider and offsets the temperature setting during increased demand periods when energy costs are high, to reduce a consumer's energy usage. Such an offset would substantially raise the temperature setting and cause the air conditioner to immediately shut off and remain off until the temperature in the space rises above the significantly raised temperature setting. This would not only allow the utility to lower energy consumption to keep the peak demand from exceeding their capacity, but also the user would be able to save on their energy bill.
But this method of offsetting a thermostat's temperature setting cannot always be relied upon to reduce air conditioner operation and energy consumption, because an occupant may still lower the temperature setting and override the offset. For example, if in response to a utility signal indicating an increase in price rate, a thermostat offset its 72° Fahrenheit temperature setting to 80° Fahrenheit and displayed indicia of a high energy price rate, an occupant of the space may see the 80° set point and lower the setting back to 70° to override the offset. In this case, the utility would not succeed in curbing energy consumption during a peak demand period.